DESCRIPTION: (Adapted by the Investigator's Abstract) The investigators in this project will take advantage of a large and unique population to identify the role of salt-sensitivity of blood pressure in the pathogenesis of hypertension. They will re-examine approximately 750 normal and hypertensive subjects who were carefully characterized in terms of blood pressure response to salt loading and depletion as long as 23 years ago to identify physiological factors which may contribute to salt-sensitivity of blood pressure. They will confirm preliminary observations suggesting that salt sensitivity in normotensive subjects predicts the subsequent development of hypertension with aging. In addition, longitudinal observations in patients previously known to have hypertension as well as in normotensives will determine whether salt-sensitivity or salt-resistance of blood pressure are associated with differences in the risk for development of specific forms of cardiovascular (stroke, angina, myocardial infarction, congestive heart failure), renal, and metabolic (diabetes mellitus) disorders.